1. Field of the Invention
The invention relates to an optical switching device and, for example, to an optical switching device suitable for converting electrical information into optical signals and treating them.
2. Description of the Prior Art
For computers, the structure called Neumann-type is the mainstream, which comprises an input unit receiving information, a memory storing information, an arithmetic and logic unit for calculation and so on, an output unit outputting processed information to the outside of the computer, and a control unit operating these units according to a prescribed procedure, and the above respective units accomplish sequentially operations in prescribed order of the procedure.
Recently, a demand for high-speed operation of computers, particularly for high-speed processing of picture image and patterning, has been enhanced, and especially for treating two-dimensional information such as image process, the above sequential processing method can not fully meet the demand for high-speed processing.
In order to overcome this fault, an optical computer has been proposed, which use photon (light quantum) in place of electron flow (as information medium).
An optical switching device has also been recently manufactured (on an experimental basis), using materials, for example, liquid crystal, lithium niobate, gadolinium-gallium-garnet (GGG), gallium-arsenic, gallium-aluminium, and lead-lanthanum-zirconium-titanium alloy. In applying these optical switching devices to the above method, however, because of the structural problem, the dimensional problem in integrating, the difficulties in industrialization for its complicated structure and the problem in the access to materials, it is even said that there is no possibility of being put to practical use in the future. The switching response time of the switching device formed of the inorganic elements is in the range of nano-second (10-9 second) order, and therefore can not completely meet a demand for a quick response as to make superhigh-speed processing of information signals in an optical computer possible.